A hay baler or a baler for other crop materials generally comprises a vehicle structure or housing movable in a direction of advance along a swath of mown crop material which has previously been raked or tedded to form hay or which may be displaced across a field to pick up crop material such as straw discharged from a reaper, combine or the like.
Conventional hay balers may have a press channel extending in the direction of travel of the vehicle and provided with a ram or plunger adapted to compact crop material feed in this channel into a bale of a standard size. When the compacted material has reached this size, needles or other tying means knot a twine or wire about the compacted mass to form the bale which, as a further mass of crop material is advanced through the press channel, is ejected in the rearward discharge end of the channel. Since the ram and tying mechanism operate substantially periodically or intermittently, a transverse-feed mechanism may be provided to introduce crop material into a lateral opening of the baling channel in a retracted position of the ram. After this mechanism has moved out of the path of the ram, the latter becomes effective to compact the freshly introduced crop material against the previously formed bale. The transverse-feed mechanism thus operates synchronously with, but in phase-shifted relationship to, the press ram and both may be provided with a common drive.
The transverse-feed mechanism may include a trough or the like extending transversely of the press channel and, therefore, generally transverse to the direction of movement of the baler travel direction and may be provided with a feed fork or the like describing an elliptical or kidney-shaped motion whereby the fork sweeps close to the bottom of the trough in the direction of the press channel, elevates its tines at the end of their travel ends to lift the crop material into the press channel through the aforementioned lateral opening and then retracts rearwardly at some distance above the floor of the trough so that crop material can continuously feed into the trough during the feed and return strokes of the mechanism.
Various systems have been provided to pick up the crop material and the system of concern to the present invention makes use of a pickup drum rotatable about a substantially horizontal axis transverse to the press channel, parallel to the transverse-feed trough and perpendicular to the direction of displacement of the baler. The drum, which may extend over the full throat of the machine, may be provided with radially or secantially projecting tines, tongues or fingers which engage the crop material and lift it over the drum and into the transverse-feed trough.
Experience has shown that such systems are not always satisfactory because the crop material may fall back along the rising surface of the drum and delivered irregularly to the trough. Consequently, it has been proposed to provide an auxiliary mechanism in the region of the drum, e.g. above the latter, and including rotary tines or the like to assist in feeding the material into the transverse feed trough. The auxiliary mechanism may include a further drum having an array of tines, tongues or fingers, rotatable about an axis parallel to the axis of the pickup drum and describing a circular motion with the projecting members being effective only at their lowermost position of the circular orbit to engage the crop material. The auxiliary mechanism thus may be considered a rotatable rake, the greater part of the travel of the tines thereof being useless for any displacement of the crop material.
The rotatable rake or rotary fingers or tines are driven periodically or continuously with a phase-shifted relationship with respect to the operation of the tranverse-feed mechanism which, as noted, is shifted out of phase with respect to the motion of the compression ram. Since the rotatable rake is effective only in the lowermost portions of the rack tines, the auxiliary mechanism provides insufficient guidance for the crop material overshooting the pickup drum and the system is not capable of providing any pre-compaction within the feed trough as is desirable for efficient operation of the tranverse-feed mechanism and the press ram. Furthermore, sudden increases in the pickup of the crop, resulting from nonuniform swath formation, may result in jamming or clogging of the pickup and auxiliary devices.